High-voltage electric circuit breaker



Dec. 24, 1968 E. J. CASEY ET AL 3,418,439

HIGH-VOLTAGE ELECTRIC CIRCUIT BREAKER Filed Oct. 21, 1965 3 Sheets-Sheet1 F/g. Z.

44 INVENTORS. M 7061 EDWARD J. CASEY,

MILTON L.HE//vrz BY Wm M ATTORNEY Dec. 24, 1968 E. J. CASEY ETALHIGH-VOLTAGE ELECTRIC CIRCUIT BREAKER HE/NTZ,

5 Sheets-Sheet 2 INVENTORS. EDWARD J. CASEY MILTON L Filed Oct. 21, 1965A 7' TORNE Y Dec. 24, 1968 E. J. CASEY ET AL HIGH-VOLTAGE ELECTRICCIRCUIT BREAKER 3 Sheets-Sheet 5 Filed Oct. 21, 1965 m M J R M L 7 0 VONT R r wAm WA w 0 4 EM qr g United States Patent Ofice Patented Dec. 24,1968 3,418,439 HIGH-VOLTAGE ELECTRIC CIRCUIT BREAKER Edward J. Casey,Media, and Milton L. Heintz, Newtown Square, Pa., assignors to GeneralElectric Company, a corporation of New York Filed Oct. 21, 1965, Ser.No. 499,205 Claims. (Cl. 200-144) ABSTRACT OF THE DISCLOSURE Vacuum-typecircuit breaker comprising a high voltage metal housing mounted on avertically-extending insulating support. First and second vacuuminterrupters are mounted at one side of the housing and third and fourthinterrupters at the opposite side. First and secondhorizontally-extending hollow insulators on opposite sides of thehousing respectively mount the first and fourth interrupters, whereasthe second and third interrupters are mounted directly on the housing inoffset, laterally-spaced relationship to the first and secondinsulators, respectively. The interrupters are electrically connected insuch a manner that current flows successively through the first, second,third and fourth interrupters.

This invention relates to a high voltage electric circuit breaker andrelates more particularly to a high voltage electric circuit breakerthat comprises a plurality of enclosed interrupter units electricallyconnected together in series. In a preferred embodiment of theinvention, the interrupter units are vacuum-type circuit interrupters,each comprising a sealed envelope and relatively movable contactslocated therein.

In the usual circuit breaker of this type, the seriesconnectedinterrupter units are mounted in aligned relationship to form anassembly, and an insulating housing of tubular form is provided aboutthe assembly to provide a weather-proof enclosure. The individualinterrupter units are usually operated by one or more movable operatingrods extending longitudinally of the assembly. These operating rods aretypically located in the cylindrical space between the interrupterassembly and the insulating enclosure. A disadvantage of such anarrangement is that the enclosure diameter must be relatively large inorder to accommodate both the interrupter assembly and the operatingrods, and such large diameter insulating enclosures are quite expensive.

An object of the present invention is to arrange the interrupter unitsin such a manner that inexpensive insulating enclosures of a relativelysmall diameter can be used for enclosing the interrupter units and theoperating rods.

Another object is to provide a high voltage circuit breaker that lendsitself to being constructed of modular units which can be quicklyassembled and which can be used in varying numbers to provide circuitbreakers of different voltage ratings.

Another object is to construct the circuit breaker in such a manner thatindividual interrupter units can be easily inspected and replaced, ifnecessary, without disturbing the remaining interrupter units.

In carrying out our invention in one form, we provide a high voltageelectric circuit breaker that comprises a metal housing normally at ahigh voltage and an insulating support on which the metal housing ismounted. First and second circuit interrupters are located at one sideof the housing, and third and fourth circuit interrupters are located atanother side of the housing. A first generally horizontally-extendinghollow insulator is mounted on the housing at said one side, and asecond generally horizontally-extending hollow insulator is mounted onthe housing at said other side. Means is provided for mounting the firstcircuit interrupter on one of the hollow insulators and the fourthcircuit interrupter on the other of the hollow insulators. Additionalmeans is provided for mounting the second and third interrupters on themetal housing in offset laterally-spaced relationship to said hollowinsulators. The four interrupters are electrically connected in seriesso that current can flow successively through the first, second, thirdand fourth interrupters. A pair of generally horizontally extendingoperating rods for the first and fourth interrupters, respectively, areprovided, and these operating rods extend from their respectiveinterrupters through the hollow insulators into the interior of themetal housing. Additional operating rods are provided for the second andthird interrupters, respectively, and these operating rods extend fromtheir respective interrupters into the interior of the metal housing.Located inside the metal housing and mechanically coupled to theseoperating rods is operating means for producing substantiallysimultaneous operation of the operating rods.

For a better understanding of our invention, reference may be had to thefollowing description taken in conjunction with the accompanyingdrawings, wherein:

FIG. 1 is a side elevational View, partially schematic, of a circuitbreaker embodying one form of my invention.

FIG. 2 is a plan view of the circuit breaker of FIG. 1. Certain portionsof the circuit breaker of FIG. 1 have been removed for clarification.

FIG. 3 is a sectional view taken along the line 3-3 of FIG. 2. Thecircuit breaker is shown in a closed position.

FIG. 4 is a schematic view of the circuit breaker of FIG. 3, the partsin FIG. 4 being shown in an open position.

FIG. 5 is a sectional view along the line 55 of FIG. 3.

FIG. 6 is a schematic illustration of a modified form of the invention.

FIG. 7 is an enlarged detail view of a portion of FIG. 3.

Referring now to FIG. 1, the circuit breaker shown therein comprises ametal housing 11 that is normally at a high voltage with respect toground. This housing 11 is mounted on a cylindrical column 12,preferably of porcelain, which electrically isolates the metal housing11 from ground. The lower end of the insulating support column 12 issuitably mounted on a conventional metal framework 13, which is atground potential.

The metal housing 11 serves as a support on which the interrupting unitsof the circuit breaker are mounted. These interrupting units can best beseen in FIG. 3, where four interrupting units 21, 22, 22a and 21a areshown. In a preferred form of the invention, all of these interrupterunits are substantially identical. These interrupting units can be of aconventional construction, but to facilitate an understanding of theinvention a detailed description of one of them is presentedhereinafter. The first and second interrupting units 21 and 22 arelocated at one side of the metal housing 11, and the third and fourthinterrupting units 22a and 2111 are located at an opposite side of thehousing. All the interrupting units are electrically connected togetherin series, as will soon be described.

The interrupting units at the right-hand side of the housing 11 aremounted on the housing in the same manner as those on the left-hand sideof the housing. Accordingly, the mounting of only the right-handinterrupting units will be described in detail. Corresponding parts atthe left-hand side of the housing 11 are assigned correspondingreference numerals except with the suflix a.

Each interrupting unit is preferably a vacuum-type circuit interrupterand can be of any suitable conventional design. For a more specificshowing of an interrupter suitable for use in the disclosed circuitbreaker, reference may be had to U.S. Patent 3,163,734 to Lee, assignedto the assignee of the present invention. Generally speaking, each ofthe interrupters comprises a highly-evacuated sealed envelope 30 inwhich a pair of separable butt-type contacts 31 and 32 are mounted. Thecontacts have been suitably processed to free them of sorbed gases andcontaminants that decompose in the presence of an arc to form permanentgases. The envelope 30 comprises a tubular housing 33 of insulatingmaterial and a pair of end caps 34 and 35 closing off the ends of thetubular housing and suitably sealed thereto. The right-hand contact 31(of interrupter 21) is a stationary contact that is supported on theinner end of a conductive rod 36. The conductive rod 36 projects. insealed relationship through the right-hand end of the envelope and isrigidly attached to the end cap 34 by welding.

The other contact 32 of the circuit interrupter 21 is a movable contactbrazed to the inner end of a contactactuating rod 38, referred tohereinafter as the movable contact rod. This movable contact rod 38 ismounted for substantially straight line movement along its longitudinalaxis and projects freely through an opening in the lefthand end cap 35.A flexible metallic bellows 40 is interposed between the left-hand endcap 35 and the contact rod 38 to provide a seal about the contact rodthat allows for longitudinal movement thereof without impairing thevacuum inside the envelope 10.

Opening of the circuit interrupter 21 is eflected by applying a force tothe contact rod 38 to drive the movable contact 32 to the left out ofengagement with the other contact 31. Initial separation of the contactsestablishes a circuit interrupting are between the contacts, and thisare will persist until about the time a natural current zero is reached.The are will then vanish and be prevented from reigniting by the highdielectric strength of the vacuum, thus completing thecircuit-interrupting operation.

Closing of the interrupter 21 is eflected by driving the left-handcontact 32 to the right from its open position of FIG. 4 into engagementwith the other contact 31, thus reestablishing the power circuit throughthe interrupter.

The actuating means for effecting opening and closing movement of thecontact rod 38 will soon be described in detail, but first a descriptionwill be given of the structure that is relied upon for supporting eachof the interrupters and for carrying current to and from theinterrupters.

For supporting the interrupter 21, a horizontallyextending hollowcylinder 44 of an insulating material such as porcelain, is provided. Atits left-hand end, the insulating cylinder 44 is suitably secured to themetal housing 11; and at its right-hand end, the cylinder 44 carriesmetallic structure 4 6 that is secured to the lefthand end plate 35 ofthe interrupter 21. For securing the insulating cylinder 44 to thehousing 11, a plurality of tie rods 47 of a suitable insulating materialare provided inside the cylinder 44. These tie rods 47 are clamped attheir left-hand end to a wall of the metal housing 11. The right-handend of each tie rod is threaded, and a nut 48 mounted thereon clamps ametal plate 50 against the right-hand end of the insulator 44. Asuitable stop nut 49 on each tie rod 47 limits the force applied by thenut 48. When the nuts 48 are tightened to their normal position shown,the tie rods 47 are loaded in tension and the tubular insulator 44 isloaded in compression. This preloading of the insulator '44 incompression maintains the insulator in compression even when heavytensile or bending loads are applied thereto, thus improving theinsulators ability to withstand such loads without damage. Accordingly,the tie rods are referred to hereinafter as reinforcing means for theinsulator 44.

The structure g at the end of insulator 44 is a box-like casing that hasspaced-apart end walls 50 and 52 and an integrally formed body 53connecting these end walls. The body 53 has inspection openings thereinthat are normally closed by removable covers 54 suitably attached to thebody 53. The right hand end wall 52 is attached to the end plate 35 ofthe vacuum interrupter by series of studs. As may be seen in theenlarged view of FIG. 7, these studs 56 are integral with the end plate35 of the interrupter, and nuts 57 on the studs, acting through suitableBelleville washers 58, clamp the end plate 35 to the end wall 52.

For providing a weather-proof enclosure about the vacuum interrupter 21,a hollow porcelain cylinder 60 is provided. This cylinder 60 surroundsthe envelope 30 of the interrupter and is suitably joined to the endwall 52 at its left hand end. At the right hand end of the insulatingcylinder 68, there is an end plate 62 that is suitably joined to theinsulating cylinder 60. This end plate 62 serves as one terminal of thecircuit breaker assembly.

For carrying current to and from circuit interrupter 21 a pair offlexible metallic braids 64 and 65 are provided at opposite ends of theinterrupter. Braid 64 is suitably attached at its respective oppositeends to terminal plate 62 and the stationary contact rod 36. The otherbraid 65 is suitably attached at its respective opposite ends to themovable contact rod 38 and the body 53 of the metal casing Q. Thuscurrent through the first interrupter 21 follows a path extendingsuccessively through parts 62, 64, 36, 31, 32, 38, 65, and 53.

The upper circuit interrupter is vertically spaced from the hollowinsulator 44 and is mounted directly on the wall of metallic housing 11.In this connection, the upper interrupter 22 has studs 56 integral withits left-hand end cap through which the end cap is clamped to the wallof housing 11. Suitable nuts on the studs 86 act through Bellevillewashers to perform the clamping action, in the same general manner asdepicted in FIG. 7.

For providing a weather-proof enclosure about the interrupter 22, aporcelain cylinder is provided. This porcelain cylinder 70 is suitablyjoined at its left-hand end to the metal housing 11. At the right-handend of the porcelain cylinder 70, there is an end plate 72 suitablyjoined thereto.

For carrying current to and from the upper interrupter 22, a pair offlexible metallic braids 74 and 76 are provided at its respectiveopposite ends. The braid 74 is suitably joined at its respective ends tothe end plates 72 and the stationary contact rod 36. The other braid 76is suitably joined at its respective opposite ends to the movablecontact rod 38 of interrupter 22 and the identical movable contact rod38 of interrupter 22a. Thus, current through the interrupter 22 followsa path through parts 72, 74, 36, 38 and 76.

For carrying current between the interrupters 21 and 22, a conductivestrap 80 of a high conductivity metal is suitably attached at itsrespective opposite ends to the parts 72 and 53. It will be apparentthat conductive strap 80 connects the interrupters 21 and 22 in series.It will also be apparent that the braid 76 in metal housing 11 connectsthe series-connected interrupters 21, 22 at the right hand side of themetal housing 11 in series with the seriesconnected interrupters 21a,22a at the left-hand side of the metal housing 11. Thus, all theinterrupters are electrically connected together in series.

The metal housing 11 is electrically connected to the end plates 35 ofthe two interrupters 22 and 22a, and these end plates 35 areelectrically connected to the movable contacts 38 of their respectiveinterrupters by suitable means (not shown). Thus, when the circuitbreaker is closed, the

metal housing 11 is at line potential. When the circuit breaker is open,the metal housing 11 is at approximately mid-potential with respect tothe two terminals of the circuit breaker, as will soon be explained.

During a circuit breaker-opening operation, the four circuitinterrupters are caused to open substantially simultaneously; and durnga circuit breaker closing operation, the four interrupters are caused toclose substantially simultaneously. For producing this simultaneousoperation of the four interrupters, a contact-operating linkage 9g isdisposed inside the metal housing 11, as shown in FIG. 3.

This contact-operating linkage comprises a verticallymovable actuatingrod 92 that is biased in an upward contact-opening direction by a heavycompression spring 93 at the top of housing 11 (FIG. 3). When thecircuit breaker is in its closed position, this actuating rod 92 is heldin its depressed position shown in FIG. 3 by a trip latch 94 that actson a latch roller 95 connected to the actuating rod 92. When this triplatch 94 is released, the opening spring 93 is free to expand, therebydriving the actuating rod 92 in an upward opening direction. Fortransmitting this upward opening movement of actuating rod 92 to themovable contact rods 38 of the individual interrupters, four bell cranks100 are provided. These four bell cranks 100 are respectively coupled tothe movable contact rods 38 of the four interrupters; and all the bellcranks are coupled to the common actuating rod 92. Each bell crank 100is connected to the actuating rod 92 through a link 102 that ispivotally connected at one end to the bell crank and is pivotallyconnected at its other end to the actuating rod. The pivots at therespective ends of the link 102 are designated 104 and 106. Each bellcrank 100 is mounted for pivotal movement about a stationary pivot 108carried by a suitable bracket on the metal housing 11. The couplingbetween the bell crank 100 and the movable contact rod 38 is through apivot 109 that is slidably mounted on a drive rod 110 connected to themovable contact rod.

The drive rods 110' are directly connected to the movable contact rods38 of the upper interrupters 22 and 22a. But for each of the lowerinterrupters 21 and 21a, there is an insulating intermediate rod 111disposed between the movable contact rod 38 and its drive rod 110. Eachof these insulating intermediate rods 111 is rigidly connected to themovable contact rod 3 8 and extends through one of the hollow supportinginsulators 44 into the interior of metal housing 11.

When the common actuating rod 92 is driven upwardly from its position ofFIG. 3 by the opening spring 93, as above described, the bell cranks 100to the right of the vertical actuating rod 92 are pivoted in a clockwisedirection and the bell cranks 100 to the left of the vertical actuatingrod 92 are pivoted in a counterclockwise direction. In response to suchpivotal motion of hell cranks 100, the pivots 109 on the bell cranksmove from their illustrated position of FIG. 3 toward the center ofhousing 12. After a predetermined amount of such movement, each pivot109 engages a stop 112 on the associated drive rod 110' and drives therod 110 in a contact-opening direction. More specifically, the movablecontact rods 38 of interrupters 21 and 22 are driven to the left, andthe movable contact rods 38 of interrupters 21a and 22a are driven tothe right. The stops 112, which are preferably nuts threaded on rods110, are so adjusted that they are engaged by their respective pivots109 substantially simultaneously, thereby causing the contacts of thefour interrupters to separate substantially simultaneously during acircuit breaker opening operation. FIG. 4 illustrates the interruptersand their operating linkage at the end of an opening operation.

For smoothly terminating the opening operation without significantrebound, a suitable dashpot schematically shown at 113 is provided atthe top of housing 12 adjacent the opening spring 39. The dashpotcomprises a movable plunger 114, the upward movement of which is opposedby liquid in the dashpot. The plunger 114 is engaged by a cap 116 on theactuating rod 92 after the rod 92 has moved through a predeterminedportion of the opening stroke, and thereafter retards further upwardmovement of actuating rod 92.

Closing of the circuit breaker is elfected by driving thevertically-extending common actuating rod 92 in a downward directionfrom its open position of FIG. 4. The force for such a closingopera-tion is derived from a suitable operating mechanism (not shown)coupled to the lower end of common actuating rod 92. Such downwardclosing motion of the actuating rod 92 pivots the right-hand bell cranksin a counterclockwise direction and the lefthand bell cranks in aclockwise direction. Each of these bell cranks acts through itsassociated wipe spring to drive the movable contact rod 38 in a closingdirection. After this closing action has continued sulficiently to causecontact-engagement, the bell cranks 100 continue their closing motion,compressing the wipe springs 115 and developing a clearance spacebetween the pivots 109 and their respective stops 115. When such closingaction is terminated, the parts have been restored to their position ofFIG. 3.

To insure that the contacts of all four interrupters engagesimultaneously during a closing operation, suitable adjusting means (notshown in detail) is provided between each bell crank 100 and itsassociated link 102. Each of these adjusting means preferably comprisesan eccentric portion on pivot 104 that fits in the pivot-receivingopening of link 102. The eccentric portion can be rotatably adjustedwith respect to the remainder of the pivot 104 to provide for slightchanges in the angular position of the bell crank 100 without changingthe position of link 102.

The downward closing force exerted on the actuating rod 92, in additionto closing the interrupters, recharges the opening spring 93, therebypreparing it for another opening operation. At the end of the downwardclosing travel of actuating rod 92, the trip latch 94 moves into itslatching position behind the latch roller 95, thereby latching thecircuit breaker in its closed position.

The latching mechanism 94, 95 can be of any suitable conventional typeand is therefore shown in schematic form only. In the illustratedembodiment, it comprises a latch member 94 that is pivotally mounted ona stationary pivot 120 and a reset spring 121 that biases the latchmember toward its latched position. For tripping the latch, a longinsulating rod 24 coupled to the latch member 94 is provided. When adownward tripping force is applied to this rod 124, the latch member 94is pivoted clockwise about pivot 120 to release the latch roller 95 andpermit the opening spring 93 to drive the actuating rod 92 upwardly. Thelatch-actuating rod 124 extends through the hollow insulator 12 and isadapted to receive a tripping signal at its lower end.

As pointed out hereinabove, one of the objects of my invention has beento arrange the interrupters in such a manner that inexpensive insulatingenclosures of relatively small diameter can be used for enclosing theinterrupting units and the operating rods. I have been able to achievethis objective, partially because none of the insulating enclosures 60,60a, 70, 70a, 44, 44a is required to accommodate both an interrupter andoperating rods located outside the periphery of the interrupter. In thisrespect, note that the insulating enclosures 60, 60a, 70, and 70a arecalled upon merely to enclose the interrupters. There are no rodsextending alongside the interrupters that must also be accommodated.Note that the enclosures 44 and 44a are called upon merely to enclosethe operating rods 111 and no interrupters.

I have been able to obviate operating rods running alongside theinterrupters by reason of the staggered or offset relationship of theinterrupters at a given side of the housing. With this staggeredrelationship present, an extension (111) of a centrally-located movablecontact rod 38 can be run directly from the interrupter 21 or 21a to thecontact-operating linkage 90 without interference from the otherinterrupters 22 or 22a.

It is to be noted that the only ones of the porcelain enclosures thatcarry appreciable bending loads are the enclosures 44 and 44a. I am ableto provide internally located reinforcing rods 47 for these particularenclosures without requiring a large diameter porcelain to accommodatethese rods because there are no interrupters inside these particularinsulators. With only the operating rods 111 extending therethrough,there is ample space in a small diameter enclosure 44 or 44a toaccommodate the reinforcing rods 47 and certain other structure (soon tobe described).

For distributing the total voltage approximately equally between theindividual breaks of a multi-break interrupter, it is conventional toprovide capacitors of suitable values in parallel with the breaks. Thesecapacitors can be of any suitable conventional design, but I prefer toconstruct each capacitor as an assembly of stacked ceramic elements, asshown and claimed in application S.N. 323,414,

, Mankotf et al., filed Nov. 13, 1963, now Patent No. 3,325,-

708, :and assigned to the assignee of the present invention. Thecapacitor assembly shunting the lower interrupter 21 is located in atubular enclosure 130, preferably of porcelain. This enclosure isattached by suitable brackets 131 and 132 at its opposite ends to theend plates 62 and 72 of the enclosures 60 and 70. These brackets 131,132 also serve :as conductors which electrically connect the capacitorassembly at its opposite ends to the plates 62 and 72, therebyconnecting it in parallel with interrupter 21.

The capacitor assembly shunting the upper interrupter 22 is mountedinside the porcelain enclosure 44. This capacitor assembly which isshown schematically at 135, comprises terminal conductors 136 and 137.Terminal conductor 136 is electrically and mechanically connected to endplate 50, and terminal conductor 137 is electrically and mechanicallyconnected to the adjacent wall of housing 11. Because there is nointerrupter located inside the enclosure 44, there is ample roomavailable for the capacitor assembly 135437. Locating the capacitorassembly 135437 inside the enclosure 44 eliminates the need for :aseparate weatherproof enclosure, such as 130, for this capacitorassembly.

The capacitor assemb ies on the left hand side of the metal housing 12are mounted and are electrically connected in the power circuit insubstantially the same manner as those, described hereinabove, on theright hand side of metal housing 12. The same reference numerals areused for corresponding capacitor parts at the two sides of the metalhousing except the suffix a is attached to those at the left hand side.Since the capacitors at the left hand side of the metal housing 12 aresubstantially the same as those at the right hand side of the metalhousing, it will be apparent that when the circuit breaker is open themetal housing is at substantially a mid-potential with respect to theterminals of the circuit breaker.

It will be apparent that my circuit breaker is constructed fromidentical modules assembled together in a building block type ofconstruction. In this connection, the overall assembly of interruptersat the right hand side of the metal housing 11 is identical to theoverall assembly of interrupters at the left-hand side of the metalhousing; the four vacuum interrupters 21, 22, 21a and 22a are identical;the or enclosures 60, 70, 70a and 60a are identical; each of thesubassemblies that comprises an enclosure, such as 60, and a vacuuminterrupter, such as 21, mounted therein is identical; and each of thesupporting subassemblies 44, 47 and 44a, 47a is identical. The use ofsuch identical modules facilitates construction of and assembly of themodules by high speed assembly line techniques.

Each module has a predetermined volt-age rating; and within certainpractical limits, from these modules a circuit breaker having a voltagerating of any desired value can be built up. The voltage rating of thebuilt-up breaker will be equal to the number of modules multiplied bythe voltage rating of each module. For example, if a breaker having avoltage rating of half that depicted in FIG. 1 is desired, the modulesat one side of the circuit breaker housing 11 can be omitted. Or if abreaker with a higher voltage rating is desired, one or more additionalmodules, each comprising an enclosure such :as 60 and a vacuuminterrupter such as 21 can be provided. As shown in FIG. 6, theseadditional modules, designated 60c, can be mounted beneath the lowerassembly 44, 60 in a horizontally extending row comprising twoinsulators 44c, each identical to the insulator 44 of FIG. 1. It will,of course, be necessary to provide a taller housing 11 and suitable bellcranks inside it to provide for operation of interrupter 60csimultaneously with the other interrupters.

The individual interrupters of my circuit breaker assembly can bereadily inspected and replaced, if necessary, without disturbing theremaining interrupting units. In this connection, a pair of coveredopenings are provided in the metal housing 11. The removable covers forthese openings are shown at 141 and 142 in FIG. 1. Suitable inspectionholes 143 covered by a transparent material, such as shatter-proofglass, are provided in the covers. These inspection holes line up withthe wipe mechanisms 109-112; and through these inspection holes 143, thewipe present in any one of the interrupters can be easily determined. Ifany adjustment is necessary, the cover 141 or 142 can be removed, andthe adjusment made by suitably adjusting the corresponding stop 112. Ifit is desired to replace either of the upper interrupters 22; the cover141 on housing 11 is removed and the associated bell crank is suitablydisconnected from its contact rod by removing the stop nut 112. Then,the nuts on studs 56 are removed, and'the interrupter is withdrawn fromits enclosure 70th'rough-the outer end of the enclosure, after the coverplate 72 has been suitably removed. If. it is desired to replace eitherof the lower interrupters 21, the cover 54 on the intermediate casing 53is first removed. Through the opening in casing 53, the insulatingoperating rod 111 is disconnected from contact rod 38. Thereafter, thenuts on studs 56 of the interrupter are removed, and the interrupter canthen be withdrawn from its enclosure 60 or 60a through the opposite endof the enclosure. It will be apparent that removal of any one of theseinterrupters can be effected without disturbing the other interrupters.Similarly, the removed interrupter can be replaced with anotherinterrupter without disturbing the remaining interrupters.

While We have shown and described particular embodiments of ourinvention, it will be obvious to those skilled in the art that variouschanges and modifications may be made without departing from ourinvention in its broader espect; and We, therefore, intend in theappended claims to cover all such changes and modifications as fallwithin the true spirit and scope of our invention.

What we claim as new and desire to secure by Letters Patent of theUnited States is:

1. A high voltage electric circuit breaker comprising:

(a) a metal housing normally at a high voltage,

(1)) an insulating support on which said metal housing is mounted,

(c) first and second circuit interrupters located at one side of saidhousing and third and fourth circuit interru-pters located at anotherside of said housing,

(d) a first generally horizontally-extending hollow insulator mounted onsaid housing at said one side and a second generallyhorizontally-extending hollow insulator mounted on said housing at saidother side,

. (e) means for mounting said first circuit interrupter on one of saidlhOllOW insulators and said fourth circuit interrupter on the other ofsaid hollow insulators,

('f) means for mounting said second and third interrupters on saidhousing in offset laterally-spaced relationship to said first and secondhollow insulators, respectively,

(g) means for electrically connecting said four interrupters in seriesso that current can flow successively through said first, second, thirdand fourth interrupters,

(h) a pair of generally horizontally-extending operating rods for saidfirst and fourth inter upters, respectively; said operating rodsextending from their respective interrupters through said hollowinsulators into the interior of said metal housing,

(i) additional operating rods for said second and third interrupters,respectively, extending from said second and third interrupters,respectively, into the interior of said metal housing,

(j) and means for producing substantially simultaneous operation of saidoperating rods comprising an actuating member located inside said metalhousing and mechanically coupled to said operating rods.

2. The circuit breaker of claim 1 in which:

(a) said second and third interrupters are disposed in vertically-spacedrelationship to said hollow insulators,

(b) said second and third interrupters are generally aligned with eachother, and

(c) said first and fourth interrupters are aligned with each other.

3. The circuit breaker of claim 1 in which:

(a) said second and third interrupters are disposed in vertically-spacedrelationship to said hollow insulators,

(b) said second and third interrupters are aligned with each other,

(c) said first and fourth interrupters are generally aligned with eachother,

(d) said actuating member is movable in a generally vertical direction,

(e) said operating rods are movable in a generally horizontal directionto operate said interrupters, and

(f) said means for producing substantially simultaneous operation ofsaid operating rods comprises coupling means connected between saidverticallymovable actuating member and said operating rods forconverting the generally vertical movement of said actuating member intogenerally horizontal movement of said operating rods.

4. A high voltage electric circuit breaker comprising:

(a) a metal housing normally at a high voltage,

(b) a generally vertically-extending insulating support on which saidmetal housing is mounted,

(-c) first and second circuit interrupters located at one side of saidhousing and third and fourth circuit interrupters located at anotherside of said housing,

(d) a first hollow insulator mounted on said housing at said one sideand a second hollow insulator mounted on said housing at said otherside, said hollow insulators extending transversely of saidverticallyextending support,

(e) means for mounting said first circuit interrupter on one of saidhollow insulators and said fourth circuit interrupter on the other ofsaid hollow insulators,

(f) means for mounting said second and third interrupters on saidhousing in offset laterally-spaced relationship to said first and secondhollow insulators, respectively,

g) means for electrically connecting said four interrupters in series sothat current can flow successively through said first, second, third andfourth interrupters,

(h) a pair of operating rods for said first and fourth interrupters,respectively; said operating rods extending from their respectiveinterrupters through said hollow insulators into the interior of saidmetal housing,

(i) additional operating rods for said second and third interrupters,respectively, extending from said second and third interrupters,respectively, into the interior of said metal housing,

(j) and means for producing substantially simultaneous operation of saidoperating rods comprising an actuatgenerally generally ing memberlocated inside said metal housing and mechanically coupled to saidoperating rods.

5. The circuit breaker of claim 4 in which:

(a) a hollow insulating enclosure is provided about each of saidinterrupters,

(b) the insulating enclosures for said second and third interrupters aremounted on said metal housing in spaced-apart relationship to saidhollow insulators, and

(c) the insulating enclosures for said first and fourth interrupters aremounted on said hollow insulators, respectively.

6. The circuit breaker of claim 4 in combination with:

(a) capacitors respectively connected in parallel with said fourinterrupters,

(b) means for mounting the capacitor that is in parallel with the secondinterrupter inside the hollow insulator that mounts said firstinterrupter, and

(0) means for mounting the capacitor that is in parallel with the thirdinterrupter inside the hollow insulator that mounts said fourthinterrupter.

7. The circuit breaker of claim 4 in which said circuit interrupters arevacuum-type interrupters, each comprising a highly evacuated envelopeand a pair of relatively movable contacts located inside said envelope,one of said contacts being connected to an associated one of saidoperating rods.

8, A circuit breaker as set forth in claim 4 and further includingreinforcing means comprising tie rods located inside of each of saidhollow insulators and extending longitudinally thereof for increasingthe load-carrying capacity of said hollow insulator, said interruptersbeing located outside the interior of said hollow insulators.

9. The circuit breaker of claim 4 in which:

(a) each of said interrupters comprises an envelope having a pair ofopposed ends, one of which faces said metal housing and the other ofwhich faces in a generally opposite direction,

(b) interrupter supporting means is provided for supporting each of saidinterrupters at the end of said envelope facing said metal housing,

(c) aocess openings are provided in said circuit breaker adjacent saidinternupter supporting means for permitting disassem'bly of saidsupporting means, and

(d) an opening for each envelope larger than said envelope is present inthe circuit breaker adjacent said other end of said envelope throughwhich said interrupter may be removed from said circuit breakerindependently of the other interrupters after said supporting means hasbeen disassembled.

10. The circuit breaker of claim 1 in which said second and thirdinterrupters each have one end electrically connected to said metalhousing both when the circuit breaker is closed and opened.

References Cited UNITED STATES PATENTS 3,123,698 3/ 1964 Waterton.3,214,557 10/ 1965 Pflanz. 3,352,988 11/1967 Wachta et al.

FOREIGN PATENTS 1,152,740 8/1963 Germany.

ROBERT S. MACON, Primary Examiner.

US. Cl. X.R. 200l45

